Electric vehicles and many other devices may rely on a battery to store electrical power.
Generally, electric vehicles differ from conventional motor vehicles because electric vehicles selectively drive the vehicle using one or more battery-powered electric machines. Conventional motor vehicles, by contrast, rely exclusively on the internal combustion engine. Electric vehicles may use electric machines instead of, or in addition to, to the internal combustion engine. Example electric vehicles include hybrid electric vehicles (HEV's), plug in hybrid electric vehicles (PHEV's), and battery electric vehicles (BEV's).
Electric vehicles may be equipped with a battery configured to store electrical power for powering the electric machine. The batteries are charged prior to use, and recharged when the electric power in the battery becomes depleted.
A battery charger is typically used to charge batteries. In some electric vehicles, the electric machine may be used as a generator that is powered by the internal combustion engine in order to generate electrical power to charge the battery. Charging adds power to batteries. It can be difficult to determine when an appropriate amount of power has been added back to the battery during a charge. Adding too much power can cause the battery to become overcharged.